As expected, Blizzard has disabled the Diablo III auction houses today, locking down all current pending auctions and preventing new items from being sold going forward. Blizzard announced its intention to shut down both the real-money and virtual in game auction houses late last year.
If you visit the Auction House now, you'll see that it is no longer functional and is accompanied by the following message: "The Auction House is shutting down. You must claim your items from the Completed tab by 6/24. Existing auctions will complete based on the time remaining."